Sleep regression 7 months old

Our 7th month old is regressing with sleep.

We put her to bed at 7pm and she’s waking up at 12, 2, 4, 6. She use to sleep 7pm-6am.When she wakes up she will drink a 4 ounce bottle at times.

Here are the factors..

- has two teeth but no other teeth growing in. Doctor just checked

- we just finished exclusively breastfeeding. The last month we have been giving her formula and solids only.

- our bed time routine consists of 6pm solids,6:30 bath, 6:50 story, 7:00 asleep.

Any suggestions on how to get her to sleep through the night again?

Thanks!